Ground anchor

ABSTRACT

A ground anchor includes a plurality of resistance plates hingedly connected with one another in order to slantly drive them from a predetermined depth so that they are set in such a manner that their maximum effective bearing or resisting surfaces may be easily directed substantially toward the direction of the tension force applied thereto. These resistance plates are held stationarily colinear or coplanar, until they reach the predetermined setting depth, by a regulating or retaining member and the force applied to the regulating member for securely holding these resistance plates in said stationary and coplanar state is released when they reach the predetermined depth from the ground surface, whereby they are slantly driven into the soil in desired directions.

United States Patent [72] Inventors Hlkoltsu Watanabe No. 5-13,l-chrome, Ehara-cho, Nakano-ku; afllflsnma V No. 4-8, l-chome,Ehara-cho, Nakano-ku, both of Tokyo, Japan [21] AppLNo. 848,570

[22] Filed Aug. 8, 1969 [45] Patented Aug. 31, 1971 [32] Priority Nov.29, 1968, Feb. 14, 1969 [3 3 1 Japan [3 l 43/86924 and 44/ 12239 [54]GROUND ANCHOR 4 Claims, 17 Drawing Figs.

[56] References Cited UNITED STATES PATENTS 4/1934 Bullard PrimaryExaminer-Price C. Faw, Jr. Attarney-Jecies and Greenside ABSTRA C'll: Aground anchor includes a plurality of resistance plates hingedlyconnected with one another in order to slantly drive them from apredetermined depth so that they are set in such a manner that theirmaximum effective bearing or resisting surfaces may be easily directedsubstantially toward the direction of the tension force applied thereto.These resistance plates are held stationarily colinear or coplanar,until they reach the predetermined setting depth, by a regulating orretaining member and the force applied to the regulating member forsecurely holding these resistance plates in said stationary and coplanarstate is released when they reach the predetermined depth from theground surface, whereby they are slantly driven into the soil in desireddirections.

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Hikoitsu watanabe and Sanj i Gcnma Their Attorneys GROIUND ANCHORBACKGROUND OF THE INVENTION The present invention relates to a groundanchor for retaining one end of a guy element which is used forreinforcing a supporting structure such as a pole, an antenna or thelike.

A conventional anchor of the type described is generally comprised of arectangular steel resistance plate having its leading edge sharpened anda guy rod pivotably mounted upon the upper surface of the steel plate.The anchor is set to a predetermined depth into the soil by driving theanchor in direction of the tension which is applied to the resistanceplate. Thereafter, the resistance plate is'pulled back toward the groundsurface via the guy rod so that the resistance plate may be rotatedthrough an angle of 90 whereby the maximum effective soil bearing orresisting surface of the resistant plate may be directed substantiallyat a right angle with respect to said direction of the tension.Alternatively, the resistance plate is curved so that it may be slantlydriven into the soil, whereby The maximum effective soil resistingsurface of the plate may be directed toward said direction of tension.

In the first driving method, when the resistance plate is rotated viathe guy rod upon completion of the driving operation, it is possible todo so only when the resistance applied to the resistance plate beingrotated is less. In other words, the resistance plate may be rotated toa desired direction as described above only in theory namely whenlocated in air or fluid. However, when the resistance plate is rotatedin soil which has been compressed for a long time, the soil resistanceapplied to the resistance plate is extremely high so that the lattercannot be rotated smoothly to a desired direction. This presents anespecially serious problem when the dimensions of the resistance plateare made large in order to provide a strong resistance against strongpull. Consequently, it is almost impossible to rotate a large-sizedresistance plate in the soil because of the strong soil resistanceencountered as described above. Even if the resistance plate could berotated, the cavity formed around the resistance plate during therotation of the same would be increased as the dimensions andconfiguration of the resistance plate are increased, so that the soilbearing or resisting force of the resistance plate and consequently theresistance against the tension or pull would be inevitably reduced.

In the second driving method described above, as the curved resistanceplate is driven into the soil, the direction of applying the drivingforce or impact must be changed accordingly, furthermore, when theinitial driving angle of the resistance plate is not correct, theresistance plate cannot be set in a correct position. It will be seenthat this method is very difficult and tedious in practice. In the worstcase, depending upon the deviation of the initial driving angle of theresistance plates and on the soil conditions, the final angular positionof the resistance plate with respect to the direction of tension will bemuch varied, so that such resistance of the plates will greatly varyfrom case to case.

SUMMARY OF THE INVENTION In view of the above, the primary object of thepresent invention is to provide a novel ground anchor which completelyor at least substantially eliminates the above described defectsencountered in case of the conventional ground anchor.

On of the features which are believed to be characteristic of thepresent invention resides in the fact that the resistance plate of theground anchor is comprised of a plurality of smallsized resistanceplates which can be easily driven slantly and which are hingedlyconnected with one another is such a manner that they may be inclinedinwardly with respect to each other within a predetermined angle ofinclination, whereby they can together provide the maximum effectiveresisting surface which can otherwise be provided only by onelarge-sized resistance plate.

Another feature of the present invention is that the resistance platesmay be locked together stationarily in one coplanar straight block bymeans of a regulating or retaining plate, so that they can be easilydriven straight into the ground to a predetermined depth. The lockingarrangement can be released from the ground surface so the that theresistance plates may be slantly driven after having reached saidpredetermined depth. In this case, the resistance plates following thefirst or leading resistance plate can easily follow the passage formedby the leading resistance plate without themselves forming any cavity inthe soil, because they are hingedly connected as described above,whereby these resistance plates can be set in the soil with theirrespective soil bearing or resisting surface being substantiallydirected at right angles to the direction of the pull.

According to the present invention, a ground anchor which can be easilyand accurately driven into the soil and will provide a sufficient soilresistance against strong pull may be provided.

The above and other objects, features and advantages of the presentinvention will become more apparent from the'following description withreference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS FIG. l is a front view of one embodimentof a ground anchor according to the present invention,

FIG. 2 is a side view thereof,

FIG. 3 is a detailed exploded view of a first and a second resistanceplates thereof,

FIG. d to h are for explanation of the driving steps of the anchor ofthe first embodiment,

FIG. 9 is a side view of another embodiment of a ground anchor includingthree resistance plates,

FIG. It) is a front view of a still another embodiment of the presentinvention,

FIG. II is a side view thereof, FIGS. 12 to 116 are for explanation ofdriving steps thereof, and

FIG. i7 is a side view of a further embodiment of the present inventionincluding three resistance plates.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. I and 2 are front andside views of an anchor generally indicated in its entirety by referencenumeral 20, which comprises a first resistance plate 22 having theconfiguration of a pentagon and having a sharp leading edge 211 whichserves as a driving edge, a second resistance plate 23 disposed insuccession with the first resistance plate 22 and having theconfiguration of a rectangle, a regulating plate 241 which serves as alink for connecting the first and second resistance resistance plates 22and 23, and a guy plate 25 and a connecting rod 26.

At the trailing or upper edge of the first resistance plate 22 is formeda notch 27, as shown in FIG. 3 having a pair of slots 28 substantiallysymmetrical reference to the longitudinal axis of the resistance plate22. A pair of slots 29 are formed in the leading or lower edge of thesecond resistance plate 22 in opposed relation with the pair of slots 2%of the first resistance plate 22. llnto the slots 29 are fitted the baseportions of connecting and stopping plates 30 which are securely fixedto the second resistance plate 23 by welding or the like in such amanner that the connecting plates 3i) are at right angles rela tive tothe plate 23. A shaft 31 is rotatably received between these plates 30in the vicinity of the leading ends thereof. This shaft 31 is disposedwithin the notch 27 of the first resistance plate 22 and is securelyjoined thereto by welding or the like. Therefore, the first and secondresistance plates 22 and 23 are joined with each other in such a mannerthat they may rotate Thus, it will be seen that each of the plates 30welded to the second resistance plate 23 is colinear with itscorresponding stop plate 32 welded to the first resistance plate 22.

The leading or lower end 33 of each connection plate 30 is rounded so asto have an arc whose center coincides with the axis of the shaft 31. Onthe other hand, each of the stop plates 32 has an arcuate notch 34 tomate with the arcuate end 33 of the connection plate 30. Therefore, whenthe first and second resistance plates are interconnected with eachother as described hereinabove, the ends 33 of the plates 30 may bepermitted to move in contact with the notches 34 of the stop plates 32when the first and second resistance plates 22 and 23 are rotated withrespect to each other in a manner as described above.

An outer branch 35 of each of the stop plates 32 is so designed that thearm 35 rides over the shaft 31 and then contacts with the outer surfaceof the plate 30 when both of the resistance plates 22 and 23 arecoplanar, while an inner arm 34 of the stop plate 32 terminates at asuitable point below the shaft 31, that is a point of the end 33 of theplate 30, as best shown in FIG. 2.

Consequently, when the first resistance plate 22 is to be rotated in thedirection indicated by the arrow (11') in FIG. 2, the rotation of thefirst resistance plate 22 is prevented because the outer arm 35 of thestop plates 32 are pressed against the outer side edges of the plates30. However, when the first resistance plate 22 is to be rotated in thedirection indicated by the arrow (ii) in FIG. 2, the rotation of theplate 22 in this direction is possible because the inner arms 36 mayslide over the arcuate ends 33.

In this case, a permissible range of angle of rotation of the firstresistance plate 22 in the direction indicated by the arrow (ll) isdetermined by the point where the inner arm 36 of the stop plate 32leaves the end 33 of the connection plate 30. in other words, the rangeis determined by the length of the inner arm 36, thereby limiting anangle of inclination between the first and second resistance plates 22and 23.

Referring back to FIG. 3, at the trailing or upper edge of the secondresistance plate 23 is formed a cross-shaped portion 37 the verticalslot of which is colinear with the longitudinal axis of the secondresistance plate 23. Into this cross-shaped slot 37 is fitted a rotaryplate 38 whose construction is substantially similar to that of theplate 30 welded to the leading edge of the second resistance plate 23.At a position adjacent to the leading edge of the rotary plate 38 isrotatably carried a shaft 39 which in turn is disposed in the horizontalportion of the cross-shaped slot 37 and welded thereto integraltherewith, so that the rotary plate 38 may rotate about the shaft 39with respect to the second resistance plate 23. The leading edge of therotary plate 38 has the configuration of an arc whose center coincideswith the axis of the shaft 39. A stop plate 41 having a constructionsubstantially similar to the stop plate 32 mounted upon the firstresistance plate 22, is also attached upon a second resistance plate inthe cross-shaped slot 37 in the similar manner as described above. Thestop plate 41 has an arcuate notch 42 which mates with the arcuate end40 of the rotary plate 38 and an outer arm 43 of the stop plate 41 ismade longer than an inner arm thereof in order to limit the angle ofrotation of the rotary plate 38 with respect to the second resistanceplate 23 in a similar manner as described above with reference to thejoint between the first and second resistance plates 22 and 23.

Along the longitudinal axis of the rotary plate 38 is formed a slit 45extending inwardly from the trailing edge of the plate 38 and into thisslit 45 is fitted the base portion of a threaded rod 46 which is fixedlyjoined to plate 38 by welding or the like, so as to be integral with therotary plate 38.

Now referring back to FIGS. 1 and 2, a bracket 47 is integrally joinedto the first resistance plate 22 along the longitudinal axis thereof ata right angle with respect thereto by welding or the like, and one endof the regulating plate 24 is pivoted to the leading end of the bracket47 by means of a pin 48. The length of the regulating plate 24 is sodetermined that when the first and second resistance plates 22 and 23are held coplanar (in the same plane), the upper end portion of theregulating plate 24 abuts against the upper (or trailing) end portion ofthe rotary plate 38 in the same plane. in order to facilitate thisabutment and to prevent the separation between the rotary plate 38 andthe regulating plate 24 after they are abutted against each other.bifurcated catch pawls 49 are securely pivotably fixed to the inner sideedge of the rotary plate 38 so that the regulating plate 24 may bereadily engaged and clamped by the catches 49. In this case, theclamping force of the catches 49 must be such that when the strongexternal force is applied to the regulating plate 24, the latter must beeasily released from these catches 49.

The above described arrangement in which the upper end portion of theregulating plate 24 is firmly pressed against the upper end portion ofthe rotary plate 38 in the same plane when the first and secondresistance plates 22 and 23 are stationarily held coplanar, serves toprevent the regulating plate 24 from being moved away from the rotaryplate 38 when an external force is applied to the upperend of theregulating plate 24 by a driving rod 50 whose lower end is inscrewthreaded engagement with the threaded rod 46 of the rotary plate38. Furthermore, the provision of the catches 49 serves to clamp theregulating plate 24 to the rotary plate 38 so that the first and secondresistance plates 22 and 23 may be held coplanar when the driving rod 50is threaded together with the threaded rod 46 of the rotary plate 38.The construction of the catches 49, which readily release the regulatingplate 24 when the external force is applied thereto, serves to easilymove the regulating plate away from the rotary plate 38 when theexternal pressure applied to the upper end of the regulating plate 24 isreleased by unscrewing the driving rod 50 from the threaded rod 46, andthereafter the driving force is applied to the regulating plate 24.

The guy plate 25 is pivotably connected at a position adjacent to thecenter of the regulating plate 24 by means of a pin 51', the other endof the guy plate 25 there is securely fixed the lower end of a guy rod52 by welding or the like. The connecting pin 5! between the regulatingplate 24 and the guy plate 25 is interconnected with the shafl 39joining the rotary plate 38 with the second resistance plate 23, bymeans of the connecting rod 26 having an elongated slot 53 formed alongthe longitudinal axis thereof. Both of the connecting pin 51 and theshafl 39 are fitted into the elongated slot 53 so that this connectingrod 26 serves to prevent the connecting pin 51 and the shaft 39 frombeing spaced apart from each other beyond a predetermined distance. itis obvious that the shaft 39 must be fitted into this elongated slot 53before the shaft 39 is welded to the cross-shaped slot 37 formed at thetrailing edge of the second resistance plate 23; while the connectionpin 51 must be fitted into the elongated slot 53 and into the hole ofthe guy plate 25.

As described hereinabove, according to the construction and arrangementof the present invention, the small-sized first and second resistanceplates 22 and 23 which are easily capable of inclining or rotating withrespect to each other are joined together so as to be held coplanar witheach other and to be rotated inwardly when required, so that driving ofthe anchor of the present invention and the rotation or inclination ofthe leading elements thereof can be much facilitated when driving iseffected by the method to be described in more detail hereinafter.Therefore. both the first and second resistance plates 22 and 23 may beeasily driven into the ground in such a manner that these plates 22 and23 are directed substantially at right angles with respect to thedirection in which the tensile or pulling force is later to be applied.Furthermore, when the anchor is driven into the ground the formation ofcavities around the resistance plates can minimized, whereby sufficientforce to resist the tensile force can be provided. These are novelfeatures of the present invention.

Next the ground anchor driving method of the present invention will bedescribed with reference the FIGS. 4 and 8. The driving rod 50 has atits lower end an internally threaded hole M for threadable engagementwith the externally threaded rod Firstly, the first and secondresistance plates 22 and 23 are arranged in coplanar position and theupper end portion of the regulating plate 23 is clamped by the catches49 of the rotary plate 38. Thereafter, the jntemally threaded hole 54 isscrewed onto the threaded rod as of the rotary plate 33 so that thelower end of the driving rod 50 contacts with both of the upper ends ofthe rotary plate 38 and the regulating plate 24 as best shown in FIG. d.Thus, because of the force applied to the upper end of the regulatingplate 24 from the lower end of the driving rod 50, the regulating plate24) is firmly held against the rotary plate 33. When the driving rod 50is assembled with the ground anchor of the present invention asdescribed hereinabove, the movement of the first resistance plate 22 ispositively restricted by the regulating plate 24 so that the plate 22will not be permitted to rotate or incline inwardly (the directionindicated by the arrow ll). Concurrently, outward rotation orinclination of the first resistance plate 22 (in the direction indicatedby the arrow 1111) will not be permitted because of the outer arms as ofthe stop plates 32, as described in detail hereinabove Furthermore,since the second plate 23 must rotate or incline outwardly in order torotate or incline relative to the rotary plate 38, it is obvious thatthe second resistance plate 23 cannot rotate or incline relative .to therotary plate33. Consequently, both of the first and second resistanceplates are forced to be extended in the same plane.

Next the ground anchor mounted to the driving rod 30 is held verticallyin such a manner that the driving edge 211 of the first resistance plate22 is located at a driving position upon the ground. Thereafter, thedriving force or impact is applied to the upper end of the driving rod5050 that the whole assembly is driven straight into, the soil. Once theanchor is driven into a predetermined setting depth, the drivingoperation is stopped temporarily. Then, as shown in FIG. 3, the drivingrod 50 is unscrewed to some extent from the threaded rod 46, therebymoving the lower end of the driving rod away from the upper end of theregulating plate 2 3.

Now, the driving operation is restarted. In this case, because of thesoil resistance acting upon the regulating plate which is pulled by thebracket 37 and driven into the soil, the guy plate as, the guy rod 52,the connecting rod 2s, etc. stronger resistance is applied to the innersurface of the first resistance plate 22 so that the latter longer canbe driven straight into the soil. Consequently, as shown in H6. b thefirst resistance plate 22 is forced to inwardly incline or rotate aboutthe shaft 31 end now becomes driven slantly into the soil. In this case,it will be obvious that if the angle of inclination of the firstresistance plate 22 relative to the second resistance plate 23 werepermitted to increase unlimitedly, then only the first resistance plate22 would be driven slantly and finally move to a right angle positionrelative to the second resistance plate 23 so that the slanted drivingof the second resistance plate 23 would become impossible. This can beprevented by the provision of the connection plates 30 welded to thesecond resistance plate 23 and the stop plates 32 welded to the firstresistance plate 22, both of which cooperate with each other so as torestrict the angle of inclination of the first resistance plate 22relative to the second resistance plate 23 as described hereinabove.Therefore, the angle of inclination of the first resistance plate 22 canbe restricted within a range which permits also the slant driving of thesecond resistance plate 23.

As the driving operation is continued, the second resistance plate 23 isinwardly rotated or inclined about the shaft 39 and is driven along thedriven passage of the first resistance plate 22. Thus, both of the firstand second resistance plates 22 and 23 are slantly driven further intothe soil with the angle between the plates being maintained and finally,as shown in FIG. 7, they are set in the soil in such a manner that theirinner (upper) soil bearing surfaces are suitably inclined with respectto each other and to the direction along whichthe tensile force isapplied thereto. In this state, the driving rod 30 is completelyunscrewed from the threaded rod iti and is pulled out so that only theanchor 20 is completely set in the soil as shown in H0. 3.

Thus, the anchor 20 as now set is comprised of the first resistanceplate 22 whose leading edge is the point of application of force fromthe regulating plate the second resistance plate 23 whose trailing edgeis the point of application of force from the connection plates as andthe regulating plate and the connecting rod as integrally joinedtogether by means of the guy plate 25. Therefore, the joint, that is thepin 51 connecting the regulating plate M and the connecting rod 26 withthe guy plate 25, becomes the overall point of application of force ofthe anchor structure 20 of the present invention. Thus, the anchor 20can provide sufificiently strong and reliable resistance against thetensile force applied thereto.

In the first embodiment of the present invention, the anchor 20 has beenshown as having only two resistance plates 22 and 23. but it is to beunderstood that as shown in F16. 9 the anchor 20 may includes resistanceplates 22, 23 and 23s or more than four resistance plates if required.Also in the first embodiment, the driving rod Slit intersects with theregulating plate M as shown in F l6. 7. The reason is that the drivingrod 30 is made of a round bar while the regulating plate 2d, bears uponit so that when the driving rod 30 is forced into the soil after itengages the regulating plate 22, the latter is forced outwardly alongthe surface of the driving rod 5h so that they may be easily crossedwith each other.

In the first embodiment described hereinabove with reference to FIGS. land 2, the impact applied to the driving rod 50 is transmitted to thefirst and second resistance plates 22 and 23 through the threaded rod asof the rotary plate 3%. Therefore, when the driving rod 3 is partiallyunscrewed from the threaded rod as to some extent in order to move thelower end of the driving rod 50 away from the upper end of theregulating plate 24), and when the stronger impact is applied to thethreaded rod as if required, excess force will be applied to theconnection between the threaded rod as and the driving rod 50 so thatthere is a danger that the connection might be broken. Therefore, if the:soil conditions require a stronger driving force, it is preferable toutilize the second em bodiment shown in H68. 9 and 1141).

Referring to FIGS. 3 and lit), a ground anchor is comprised of a firstresistance plate 1122 having the configuration of a pentagon and asharp-pointed driving edge 112i, :1 second re sistance plate 1123 havingthe configuration of a rectangle, and being disposed immediately afterthe first resistance plate 122, a connecting plate 1124 serving as alink between the first and second resistance plates 1122 and 1123, a guyplate and a connecting rod 126. The first and second resisting plates1122 and R23 are hingedly joined in such a manner that a connecting andstopping plate 11311) is fitted into and welded to slot formed at theleading edge of the second resistance plate 1123 and a shaft which isrotatably carried at a position adjacent to the leading (lower) end ofthe connecting plate 113i) is fitted into and welded to a notch formedat the trailing (upper) edge of the first resistance plate 222. As inthe case of the first embodiment, the second resistance plate 1123 and arotary plate 1138 are hingedly connected with each other by fitting intoand welding to the lateral portion of a cross-shaped slot formed at thetrailing (upper) edge of the second resistance plate a shaft 139 whichis rotatably carried at a position adjacent to the leading (lower) endof the rotary plate 1133.

The above described single connecting plate 113i) is disposed along thelongitudinal axis of the first and second resistance plates 1122 and1123 contrary to the first embodiment, but it is to be understood thatmore than one connecting plate 1130 may be used in the second embodimentif required; depending upon the dimensions of the first and. secondresistance plates T22 and 123. in order to limit the possible angle ofinclination of the first resistance plate 1122 relative to the secondresistance plate T23, stop plates i132 are provided also in the secondembodiment. That is, as in the case of the first embodiment, slots areformed on opposite sides of the longitudinal (upper) edge thereof andthe stop plates 132 are fitted into these slots and welded thereto so asto be integral with the first resistance plate 122. Each of the stopplates 132 has a notch formed at the free end portion thereof. Thedimensions and configuration of the outer and inner arms which definethe notches are such that the inner side edge of the outer arm 135 is inclose contact with the second resistance plate 123 when both of theresistance plates 122 and 123 are locked in the same plane therebypreventing the first resistance plate 122 from rotating or incliningoutwardly relative to the second resistance plate 123. On the otherhand, the inner side edge of the inner arm 136 is outwardly inclined soas to provide a space between the inner branch 136 and the secondresistance plate 123, thereby permitting the inward rotation orinclination of the first resistance plate to some extent relative to thesecond resistance plate 123. That is, the first resistance plate 122 maybe inwardly rotated or inclined relative to the second resistance platewithin an angle corresponding to the angle formed between the outer andinner arms 135 and 136, namely the angle of divergence of the notch.

As compared with the first embodiment described hereinabove withreference to FIGS. 1 and 2, the number of connecting plates whichhingedly connect the first resistance plate 122 with the secondresistance plate 123, the dimensions and configurations of stop plateswhich restrict the angle of inclination and the direction of inclinationof the first resistance plate 122 with respect to the second resistanceplate 123; are different but it will be seen that they may be suitablyselected depending upon, for example, the configurations and dimensionsof the resistance plates, the impact applied to the driving rod, thesoil conditions, etc.

A bracket 147 is securely attached to the inner surface of the firstresistance plate 122 along the longitudinal axis thereof by welding orthe like. A connecting plate 124 has its one end pivotably connected tothe free end of the bracket 147 through a pin 148. The other end of theconnecting plate 124 is pivotably connected to the lower end of the guyplate 125 via a pin 151. In this case, it is preferable that the pin 151is located substantially at the center of the whole resistance bearingsurface of the first and second resistance plates 122 and 123. The upperend of the guy plate 125 is made integral with a guide tube 155 intowhich is slidably and rotatably fitted the guy rod 152. The guy rod 152has a stop ring 156 disposed at the upper end of the guide tube 155 andan engaging ring 157 spaced apart form the lower end of the guide tube155 so that the range of the slidable movement of the guy rod 152 may berestricted. The lower end portion of the guy rod is externally threadedas shown by 158 and can be screwed into a nut 159 which is securelyfixed to the inner surface of the rotary plate.138 by welding or thelike. When the guy rod 152 is screwed into the not 159 to the fullextent, the stop ring 156 carried by the guy rod 152 is forcibly pressedagainst the upper end of the guide tube 155.

One end of the connecting rod 126 is rotatably carried by the pin 151which connects the connecting plate 124 and the guy plate 125, while theother end thereof is rotatably carried by the shaft 139 of the rotaryplate 138. In this case, it is obvious that the connecting rod 126 hasits other end rotatably carried by the shaft 139 before this shaft isfitted into the cross-shaped slot formed in the trailing (upper) edge ofthe second resistance plate 123 and welded thereto. A stopper l60 isattached to the bracket 147 and 160 abuts against one side edge of theconnecting plate 124 so as to determine the minimum angle of inclinationof the plate 124 relative to the bracket 147. Another stopper 161 isattached to he guy plate 125 so as to abut against the upper side edgeof the connecting rod 126, thereby determining the minimum angle ofinclination of the connecting rod 126 relative to the guy plate 125.These stoppers 160 and 161 are adapted to be pressed against theconnecting plate 124 and the connecting rod 126. respectively, so as tohold them in position when the lower end of the guy rod 152 is screwedinto the nut 159 to the full extent. An engaging rod 146 is fitted intoa hole formed in the trailing driving rod 150 is screwed into the nut159 to the full extent so that the upper end of the guide tube 155 ispressed by the stop ring 156 of the guy'rod 152 and the stopper 161 ofthe guy plate 125 presses against the connecting rod 126, whereby theguy plate 125, the rotary plate 138 and the connecting rod 126 are heldin unison through the guy rod 152. Concurrently, the stopper 160 of thebracket 147 is pressed against the connecting plate 124 toward the firstresistance plate 122 about the pin 148 can be positively prevented. Therotation of the connecting plate 124 in the other direction (that is thedirection away from the first resistance plate 122) can be alsoprevented because the connecting rod 126 interconnected to the plate 124is prevented from the rotation by the stopper 161 of the guy plate 125.Consequently, the first and second resistance plates 122 and 123, therotary plate 138, the guy plate 125 and other movable element of theanchor 120 are all locked stationarily in union.

Next the engaging hole 154 of the driving rod 150 is fitted over theengaging rod 146 extending from the trailing (upper) edge of the rotaryplate 138, and then the assembly of the driving rod 150 and the anchor120 is vertically held in position on the ground with the leading ordriving edge 121 of the first resistance plate 122 being directed to thesetting position. The impact is applied to the upper end of the drivingrod 150 by any suitable manner known in the art, then both of the firstand second resistance plates which are held in coplanar relation asdescribed above are driven straight into the soil.

When the anchor 120 is driven into a predetermined depth, the drivingoperation is temporarily stopped and the guy rod 152 is rotated so as todisengage the externally threaded lower end portion 158 from the nut 159of the rotary plate 138. Then, all of the movable elements of the anchor120 are unlocked from each other and become free to move independentlywithin the ranges determined by their relations with one another. Inthis state, the driving operation is restarted. Then, because of thesoil resistance acting upon the plates 147, 124, 125 and the connectingrod 126, the first resistance plate 122 is caused to advance inwardlyslantly into the soil and the second resistance plate 123 follows thepassage formed by the first resistance plate 122. Finally, both of theresistance plates 122 and 123 are set in the soil as shown in FIG. 15.It is seen that in this state the soil bearing or resistant surface ofboth plates 122 and 123 are satisfactorily directed toward the directionalong which the tensile force is applied thereto. Then, the drivingoperation is stopped and the driving rod 150 is pulled out of the soilwhereby the anchor 120 will be set in the soil as shown in H0. 16. Inthe second embodiment, the anchor 120 has been described and illustratedas being comprised of only two resistance plates 122 and 123, but it isto be understood that the anchor may include four resistance plates 122,123, 123a and 123b hingedly connected with one another as shown in thethird embodiment of FIG. 17, or may include more than four resistanceplates if required. The present invention has been described withparticular reference to some preferred embodiments thereof, but it is tobe understood that variations and modifications can be effected withoutdeparting from the spirit of the present invention as describedhereinabove and as defined in the appended claims.

What is claimed is: 1. A ground anchor, comprising in combination, afirst resistance plate having a leading edge adapted to be driven intothe ground, and a trailing edge: at least one second resistance platedownstream of said trailing edge and having a front edge and a rearedge;

connecting means pivotably connecting said trailing edge with said frontedge for relative pivotal movement of said plates about a pivot axisextending transverse to the direction in which said leading edge is tobe driven into the ground;

releasable locking means for locking said plates in coplanarrelationship, including a bracket spanning said plates and havingopposite end portions pivoted to said leading edge and said rear edge,respectively;

limiting means in part pivoted to said second resistance plate and to apredetermined portion of said bracket for enabling limited angulardisplacement of said plates with reference to one another in onedirection about said pivot axis, upon release of said locking means;

and securing means pivoted to said portion of said bracket for securinga guy member to said ground anchor.

2. A ground anchor as defined in claim ll, said locking means comprisinga rotary element having one end portion connected with said secondplate, and a threaded free end portion adapted for threaded engagementwith a driving rod for driving said ground anchor into the ground.

3. A ground anchor as defined in claim 1, said connecting meanscomprising at least one connecting plate secured to said front edge andhaving an arcuate free portion projecting beyond said front edge andwith freedom of pivotal displacement into a corresponding slot at saidtrailing edge, and a shaft carried by said free portion and fast withsaid trailing edge.

4. A ground anchor as defined in claim 3, said limiting means furtherincluding at least one bifurcated limiting member partially received insaid slot and having a longer and a shorter arm located at oppositemajor surfaces of said first plate and defining between themselves anarcuate recess into which said arcuate free end extends, said armsengaging said plates and preventing relative angular displacementthereof other than said limited angular displacement.

1. A ground anchor, comprising in combination, a first resistance platehaving a leading edge adapted to be driven into the ground, and atrailing edge: at least one second resistance plate downstream of saidtrailing edge and having a front edge and a rear edge; connecting meanspivotably connecting said trailing edge with said front edge forrelative pivotal movement of said plates about a pivot axis extendingtransverse to the direction in which said leading edge is to be driveninto the ground; releasable locking means for locking said plates incoplanar relationship, incLuding a bracket spanning said plates andhaving opposite end portions pivoted to said leading edge and said rearedge, respectively; limiting means in part pivoted to said secondresistance plate and to a predetermined portion of said bracket forenabling limited angular displacement of said plates with reference toone another in one direction about said pivot axis, upon release of saidlocking means; and securing means pivoted to said portion of saidbracket for securing a guy member to said ground anchor.
 2. A groundanchor as defined in claim 1, said locking means comprising a rotaryelement having one end portion connected with said second plate, and athreaded free end portion adapted for threaded engagement with a drivingrod for driving said ground anchor into the ground.
 3. A ground anchoras defined in claim 1, said connecting means comprising at least oneconnecting plate secured to said front edge and having an arcuate freeportion projecting beyond said front edge and with freedom of pivotaldisplacement into a corresponding slot at said trailing edge, and ashaft carried by said free portion and fast with said trailing edge. 4.A ground anchor as defined in claim 3, said limiting means furtherincluding at least one bifurcated limiting member partially received insaid slot and having a longer and a shorter arm located at oppositemajor surfaces of said first plate and defining between themselves anarcuate recess into which said arcuate free end extends, said armsengaging said plates and preventing relative angular displacementthereof other than said limited angular displacement.